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Arnaldo Carvalho de Melo 7624e69465 perf map: Move seldom used ->flags field to second cacheline
So we start with:

  $ pahole -C map ~/bin/perf
  struct map {
  	union {
  		struct rb_node rb_node __attribute__((__aligned__(8))); /*     0    24 */
  		struct list_head node;                   /*     0    16 */
  	} __attribute__((__aligned__(8)));                                               /*     0    24 */
  	u64                        start;                /*    24     8 */
  	u64                        end;                  /*    32     8 */
  	_Bool                      erange_warned:1;      /*    40: 0  1 */
  	_Bool                      priv:1;               /*    40: 1  1 */

  	/* XXX 6 bits hole, try to pack */
  	/* XXX 3 bytes hole, try to pack */

  	u32                        prot;                 /*    44     4 */
  	u32                        flags;                /*    48     4 */

  	/* XXX 4 bytes hole, try to pack */

  	u64                        pgoff;                /*    56     8 */
  	/* --- cacheline 1 boundary (64 bytes) --- */
  	u64                        reloc;                /*    64     8 */
  	u32                        maj;                  /*    72     4 */
  	u32                        min;                  /*    76     4 */
  	u64                        ino;                  /*    80     8 */
  	u64                        ino_generation;       /*    88     8 */
  	u64                        (*map_ip)(struct map *, u64); /*    96     8 */
  	u64                        (*unmap_ip)(struct map *, u64); /*   104     8 */
  	struct dso *               dso;                  /*   112     8 */
  	refcount_t                 refcnt;               /*   120     4 */

  	/* size: 128, cachelines: 2, members: 17 */
  	/* sum members: 116, holes: 2, sum holes: 7 */
  	/* sum bitfield members: 2 bits, bit holes: 1, sum bit holes: 6 bits */
  	/* padding: 4 */
  	/* forced alignments: 1 */
  } __attribute__((__aligned__(8)));
  $

and 'flags' is seldom used when printing details about the map or with
the "cacheline" sort order, we can move them it to the second cacheline,
that will allow combining it with 'refcnt', that is only four bytes:

  $ pahole -C map ~/bin/perf
  struct map {
  	union {
  		struct rb_node rb_node __attribute__((__aligned__(8))); /*     0    24 */
  		struct list_head node;                   /*     0    16 */
  	} __attribute__((__aligned__(8)));                                               /*     0    24 */
  	u64                        start;                /*    24     8 */
  	u64                        end;                  /*    32     8 */
  	_Bool                      erange_warned:1;      /*    40: 0  1 */
  	_Bool                      priv:1;               /*    40: 1  1 */

  	/* XXX 6 bits hole, try to pack */
  	/* XXX 3 bytes hole, try to pack */

  	u32                        prot;                 /*    44     4 */
  	u64                        pgoff;                /*    48     8 */
  	u64                        reloc;                /*    56     8 */
  	/* --- cacheline 1 boundary (64 bytes) --- */
  	u32                        maj;                  /*    64     4 */
  	u32                        min;                  /*    68     4 */
  	u64                        ino;                  /*    72     8 */
  	u64                        ino_generation;       /*    80     8 */
  	u64                        (*map_ip)(struct map *, u64); /*    88     8 */
  	u64                        (*unmap_ip)(struct map *, u64); /*    96     8 */
  	struct dso *               dso;                  /*   104     8 */
  	refcount_t                 refcnt;               /*   112     4 */
  	u32                        flags;                /*   116     4 */

  	/* size: 120, cachelines: 2, members: 17 */
  	/* sum members: 116, holes: 1, sum holes: 3 */
  	/* sum bitfield members: 2 bits, bit holes: 1, sum bit holes: 6 bits */
  	/* forced alignments: 1 */
  	/* last cacheline: 56 bytes */
  } __attribute__((__aligned__(8)));
  $

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-2cdw3zlw1mkamaf7nqtdlxfi@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-11-18 16:51:00 -03:00
arch perf/x86/amd: Remove set but not used variable 'active' 2019-11-11 08:31:55 +01:00
block blkcg: make blkcg_print_stat() print stats only for online blkgs 2019-11-06 17:08:38 -07:00
certs PKCS#7: Refactor verify_pkcs7_signature() 2019-08-05 18:40:18 -04:00
crypto Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
Documentation Documentation: TLS: Add missing counter description 2019-11-05 18:34:06 -08:00
drivers ARM: SoC fixes 2019-11-10 13:41:59 -08:00
fs configfs regression fix for 5.4-rc 2019-11-10 12:59:34 -08:00
include Linux 5.4-rc7 2019-11-11 07:59:06 +01:00
init Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
ipc ipc/sem.c: convert to use built-in RCU list checking 2019-09-25 17:51:41 -07:00
kernel Linux 5.4-rc7 2019-11-11 07:59:06 +01:00
lib lib: Remove select of inexistant GENERIC_IO 2019-11-10 10:38:43 -08:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm: memcontrol: fix network errors from failing __GFP_ATOMIC charges 2019-11-06 08:47:50 -08:00
net vsock/virtio: fix sock refcnt holding during the shutdown 2019-11-08 12:17:50 -08:00
samples samples/bpf: fix build by setting HAVE_ATTR_TEST to zero 2019-10-31 21:39:15 +01:00
scripts Modules fixes for v5.4-rc7 2019-11-08 09:48:19 -08:00
security Linux 5.4-rc7 2019-11-11 07:59:06 +01:00
sound ASoC: Fixes for v5.4 2019-11-07 13:52:17 +01:00
tools perf map: Move seldom used ->flags field to second cacheline 2019-11-18 16:51:00 -03:00
usr kbuild: update compile-test header list for v5.4-rc2 2019-10-05 15:29:49 +09:00
virt kvm: call kvm_arch_destroy_vm if vm creation fails 2019-10-31 12:13:16 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS Linux 5.4-rc7 2019-11-11 07:59:06 +01:00
Makefile Linux 5.4-rc7 2019-11-10 16:17:15 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.